Search for exotic neutrino-electron interactions using solar neutrinos in XMASS-I

TL;DR

This study used the XMASS-I liquid xenon detector to search for exotic neutrino-electron interactions, setting new stringent limits on neutrino millicharge, magnetic moment, and dark photon couplings based on 711 days of solar neutrino data.

Contribution

First direct measurement limits on neutrino millicharge, magnetic moment, and dark photon couplings using solar neutrinos in a liquid xenon detector.

Findings

Set the most stringent limits on neutrino millicharge to 5.4×10⁻¹² e.

Established an upper limit for neutrino magnetic moment at 1.8×10⁻¹⁰ μ_B.

Constrained dark photon coupling constants in the B-L model for specific masses.

Abstract

We have searched for exotic neutrino-electron interactions that could be produced by a neutrino millicharge, by a neutrino magnetic moment, or by dark photons using solar neutrinos in the XMASS-I liquid xenon detector. We observed no significant signals in 711 days of data. We obtain an upper limit for neutrino millicharge of 5.4$\times$10$^{-12} e$ at 90\% confidence level assuming all three species of neutrino have common millicharge. We also set flavor dependent limits assuming the respective neutrino flavor is the only one carrying a millicharge, $7.3 \times 10^{-12} e$ for $\nu_e$, $1.1 \times 10^{-11} e$ for $\nu_{\mu}$, and $1.1 \times 10^{-11} e$ for $\nu_{\tau}$. These limits are the most stringent yet obtained from direct measurements. We also obtain an upper limit for the neutrino magnetic moment of 1.8$\times$10$^{-10}$ Bohr magnetons. In addition, we obtain upper limits for the coupling constant of dark photons in the $U(1)_{B-L}$ model of 1.3$\times$10$^{-6}$ if the dark photon mass is 1$\times 10^{-3}$ MeV$/c^{2}$, and 8.8$\times$10$^{-5}$ if it is 10 MeV$/c^{2}$.